000
FXUS63 KTOP 161153
AFDTOP
Area Forecast Discussion
National Weather Service Topeka KS
653 AM CDT Fri Mar 16 2018
...Update to aviation forecast discussion...
.SHORT TERM...(Today and tonight)
Issued at 420 AM CDT Fri Mar 16 2018
Early this morning a narrow mid-level ridge was shifting east of the
area as an embedded shortwave within the western-U.S. deep mid-level
trough pivoted into western Kansas. Water vapor imagery and surface
obs showed the surface and mid-level lows tracking into western
Kansas with an associated warm front extending eastward across far
northern Kansas. Southeasterly surface winds south of the warm
front supported some moisture advection and continued WAA into the
region. Water vapor imagery showed a weak embedded wave developing
over eastern Kansas ahead of the advancing shortwave. This wave
combined with some of the increased moisture, modest isentropic
lift, and some weak elevated instability supported the development
of scattered showers and isolated thunderstorms across northeast and
east central Kansas. As the mid-level low progresses east-
northeastward, it will help to shift this scattered precipitation
into far northeast Kansas after sunrise.
As the surface low advances toward the CWA today, models show the
warm front remaining fairly stationary across far northeast Kansas
through much of the daytime hours and an associated cold front
tracking from central to east central Kansas during the afternoon
hours. With the eastward-progressing surface low, winds will begin
to veer to the southwest late morning through this afternoon, which
will help to advect drier air into central and east central Kansas.
These dry conditions combined with breezy winds and dry fuels will
result in very high to extreme fire danger conditions across that
area, so a Red Flag Warning remains in effect. See the Fire Weather
Discussion below for further details. With the warm front remaining
stationary across far northern Kansas today with southerly winds
across much of the CWA, expect decent WAA into the region and have
increased temperatures a bit with highs reaching into the mid 60s to
mid 70s for locations south of the warm front. Along and north of
the warm front, expect a sharp temperature gradient due to the
increased, so highs will likely stay in the 50s.
As this drier air gets advected into the region today, the better
moisture will get shunted into northeast to far east central Kansas,
becoming co-located with the better forcing as the surface low tracks
across far northern Kansas. Ahead of the advancing dryline, models
show some relatively weak instability developing with CAPE values of
500 to maybe 1000 J/kg. But with decent deep shear present, this
instability should be enough to support some scattered thunderstorm
development along and ahead of the advancing cold front this
afternoon. However, with models showing a relatively narrow-zone of
this marginal instability, better organized storms will likely
remain confined to that region as it shifts northeastward across the
CWA. Cannot rule out the possibility of a few strong to marginally
severe storms developing, with hail being the primary hazard.
However, with backing winds across far northeast Kansas with the
placement of the warm front and advancing surface low, an isolated
brief tornado also cannot be ruled out this afternoon. As the
surface low lifts northeastward out of the CWA overnight, lingering
precipitation across far northeast Kansas will exit by the early
overnight hours. The shift to northwesterly winds behind the front
will allow low temperatures to drop into the 30s tonight.
.LONG TERM...(Saturday through Thursday)
Issued at 420 AM CDT Fri Mar 16 2018
Sfc and upper ridge will produce a dry day on Saturday with light
north winds and daytime RH values in the 35-55% range. The next
storm system will move into the central Rockies on Sunday with low
pressure at the sfc forecast to move east along the KS/OK border.
The current track of the system would favor the best chances for
rains across the southern half of the state mainly Sunday night into
Monday. The longwave pattern will amplify into the middle of next
week with a trough/ridge/trough pattern across the CONUS.
That would mean more dry weather with near avg temps during the
period.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 635 AM CDT Fri Mar 16 2018
For the 12z TAFs, short-range models show VCSH persisting near
KTOP/KFOE through the morning hours, resulting in ceiling heights
dropping to MVFR conditions. Winds will remain breezy through
much of the TAF period, veering from southeast to the west-
southwest later this afternoon and eventually to the northwest
overnight as a cold front tracks across the outlook area. Some
short-range guidance shows some isolated to scattered showers and
thunderstorms developing along the cold front this afternoon, but
the potential for any precipitation to develop near the TAF sites
has been gradually diminishing with each hourly model run. As a
result of this lower confidence, have decided to remove the
mention of VCSH for this afternoon. Models show the potential for MVFR
cigs to return to KTOP/KFOE and possibly KMHK overnight.
&&
.FIRE WEATHER...
Issued at 420 AM CDT Fri Mar 16 2018
A decent pressure gradient will be in place today as a surface low
tracks eastward across Kansas. As a dryline moves across central to
east central Kansas late morning through this afternoon,
southeasterly winds will veer to the southwest and become breezy
with gusts of 25-35mph expected. This southwesterly flow will
advect warmer and drier air into the area with highs south of the
warm front soaring into the mid 60s to low 70s and dewpoints
dropping into the 30s. These conditions combined with dry fuels
will support very high to extreme fire danger conditions across much
of central to east central Kansas. As a result, a Red Flag Warning
remains in effect for that region from 10 AM to 8 PM.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 10 AM this morning to 8 PM CDT this
evening for KSZ034>038-054>056-058-059.
&&
$$
SHORT TERM...Hennecke
LONG TERM...Omitt
AVIATION...Hennecke
FIRE WEATHER...Hennecke